1995 Safari Van

I have a 1995 Safari with 175,000 miles but a excellent van except I just purchased it and I replaced the pcv, spark plugs, wire, cap, rotor and now I have this awful miss, I only can tell the miss during idle not driving everything was perfect until I tuned this van up the only reason I did was because everything was original and I didn't want to wait until something happened and I also have a problem when I drive the van in drive I have to hold my hand on the gear shifter because sometime the van shifts to neutral, reason I can't figure out put if I hold my hand on the shifter it never does this. I'm very confused the spark plugs are gap perfect and everything was done right.